Assessment and Management of Groundwater for the Upper Mahanadi Basin using Modelling Technique
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Date
2010
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Indira Gandhi Krishi Vishwavidyalaya, Raipur
Abstract
The Visual MODFLOW can simulate hydraulic head of a multi-layered aquifer system of Upper Mahanadi watershed satisfactorily for both steady state and transient state condition. The upper Mahanadi watershed covers the the area of Dhamtari and Raipur districts of Chhattisgarh state. WinDig software was used for digitizing the watershed boundary and well locations, and Surfer software was used to convert file format as required by the model. Hydraulic conductivity and coefficient of storage for the different layers were calibrated under both steady state and transient state conditions for the year 2007 to 2009. Input data, such as fortnightly wise pumping well head and discharge, observation well head, hydraulic conductivity of different layers, storage, initial head, constant heads, evapotranspiration, recharge in the study area have been utilized for modelling groundwater flow of a multi layered aquifer system using Visual MODFLOW. The results of model calibration indicated that model can be estimated hydraulic head similar to observed head .The calibrated values of hydraulic conductivity were found to be 1.9282 x 10-5 m/s, 8.789 x10-7 m/s , and 1.3706 x 10-4 m/s, respectively for the layers I, II and III and similarly the calibrated values of storability was found to be 9.09 x 10-5 m-1, 1 x 10-9 m-1 and 3.31 x 10-4 m-1, respectively for the layers I, II and III in X, Y and Z direction. On the basis of sensitivity analysis, it can be concluded that the hydraulic conductivity is inversely proportional to head for the case of Layer-1 but there were no change in head by increasing or decreasing the values of K in the Layer-2 and Layer-3 respectively. It is concluded that by increasing the initial head values in the Layer-1 from 284.28 to290.68 m, was no appreciable change in the head. A reduction in K value by 50 % the head change was only 0.16 % increased which was not appreciated. Similarly, an increase in K value by 50 %, the decreased in the value was negligible and remained in the order of 0.001%. This indicates that the hydraulic conductivity is inversely proportional to the head. The Visual MODFLOW was applied for simulating the hydraulic heads for the years 2009 through 2010, after calibration; it was found that the available groundwater resource during Kharif season were 93819.45 ham, 94997.1 ham, 92510.95 ham and 81127 ham for the years 2009, 2010, 2011 and 2012, respectively.